services/java/com/android/server/am/ContentProviderRecord.java

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.server.am;

import android.app.IActivityManager.ContentProviderHolder;
import android.content.ComponentName;
import android.content.pm.ApplicationInfo;
import android.content.pm.ProviderInfo;
import android.os.IBinder;
import android.os.IBinder.DeathRecipient;
import android.os.Process;
import android.os.RemoteException;
import android.util.Slog;

import java.io.PrintWriter;
import java.util.HashMap;
import java.util.HashSet;

class ContentProviderRecord extends ContentProviderHolder {
    // All attached clients
    final HashSet<ProcessRecord> clients = new HashSet<ProcessRecord>();
    // Handles for non-framework processes supported by this provider
    HashMap<IBinder, ExternalProcessHandle> externalProcessTokenToHandle;
    // Count for external process for which we have no handles.
    int externalProcessNoHandleCount;
    final ActivityManagerService service;
    final int uid;
    final ApplicationInfo appInfo;
    final ComponentName name;
    ProcessRecord proc; // if non-null, hosting process.
    ProcessRecord launchingApp; // if non-null, waiting for this app to be launched.
    String stringName;

    public ContentProviderRecord(ActivityManagerService _service, ProviderInfo _info,
            ApplicationInfo ai, ComponentName _name) {
        super(_info);
        service = _service;
        uid = ai.uid;
        appInfo = ai;
        name = _name;
        noReleaseNeeded = uid == 0 || uid == Process.SYSTEM_UID;
    }

    public ContentProviderRecord(ContentProviderRecord cpr) {
        super(cpr.info);
        uid = cpr.uid;
        appInfo = cpr.appInfo;
        name = cpr.name;
        noReleaseNeeded = cpr.noReleaseNeeded;
        service = cpr.service;
    }

    public boolean canRunHere(ProcessRecord app) {
        return (info.multiprocess || info.processName.equals(app.processName))
                && (uid == Process.SYSTEM_UID || uid == app.info.uid);
    }

    public void addExternalProcessHandleLocked(IBinder token) {
        if (token == null) {
            externalProcessNoHandleCount++;
        } else {
            if (externalProcessTokenToHandle == null) {
                externalProcessTokenToHandle = new HashMap<IBinder, ExternalProcessHandle>();
            }
            ExternalProcessHandle handle = externalProcessTokenToHandle.get(token);
            if (handle == null) {
                handle = new ExternalProcessHandle(token);
                externalProcessTokenToHandle.put(token, handle);
            }
            handle.mAcquisitionCount++;
        }
    }

    public boolean removeExternalProcessHandleLocked(IBinder token) {
        if (hasExternalProcessHandles()) {
            boolean hasHandle = false;
            if (externalProcessTokenToHandle != null) {
                ExternalProcessHandle handle = externalProcessTokenToHandle.get(token);
                if (handle != null) {
                    hasHandle = true;
                    handle.mAcquisitionCount--;
                    if (handle.mAcquisitionCount == 0) {
                        removeExternalProcessHandleInternalLocked(token);
                        return true;
                    }
                }
            }
            if (!hasHandle) {
                externalProcessNoHandleCount--;
                return true;
            }
        }
        return false;
    }

    private void removeExternalProcessHandleInternalLocked(IBinder token) {
        ExternalProcessHandle handle = externalProcessTokenToHandle.get(token);
        handle.unlinkFromOwnDeathLocked();
        externalProcessTokenToHandle.remove(token);
        if (externalProcessTokenToHandle.size() == 0) {
            externalProcessTokenToHandle = null;
        }
    }

    public boolean hasExternalProcessHandles() {
        return (externalProcessTokenToHandle != null || externalProcessNoHandleCount > 0);
    }

    void dump(PrintWriter pw, String prefix) {
        pw.print(prefix); pw.print("package=");
                pw.print(info.applicationInfo.packageName);
                pw.print(" process="); pw.println(info.processName);
        pw.print(prefix); pw.print("proc="); pw.println(proc);
        if (launchingApp != null) {
            pw.print(prefix); pw.print("launchingApp="); pw.println(launchingApp);
        }
        pw.print(prefix); pw.print("uid="); pw.print(uid);
                pw.print(" provider="); pw.println(provider);
        pw.print(prefix); pw.print("name="); pw.println(info.authority);
        if (info.isSyncable || info.multiprocess || info.initOrder != 0) {
            pw.print(prefix); pw.print("isSyncable="); pw.print(info.isSyncable);
                    pw.print("multiprocess="); pw.print(info.multiprocess);
                    pw.print(" initOrder="); pw.println(info.initOrder);
        }
        if (hasExternalProcessHandles()) {
            pw.print(prefix); pw.print("externals=");
            pw.println(externalProcessTokenToHandle.size());
        }
        if (clients.size() > 0) {
            pw.print(prefix); pw.println("Clients:");
            for (ProcessRecord cproc : clients) {
                pw.print(prefix); pw.print("  - "); pw.println(cproc.toShortString());
            }
        }
    }

    @Override
    public String toString() {
        if (stringName != null) {
            return stringName;
        }
        StringBuilder sb = new StringBuilder(128);
        sb.append("ContentProviderRecord{");
        sb.append(Integer.toHexString(System.identityHashCode(this)));
        sb.append(' ');
        sb.append(name.flattenToShortString());
        sb.append('}');
        return stringName = sb.toString();
    }

    // This class represents a handle from an external process to a provider.
    private class ExternalProcessHandle implements DeathRecipient {
        private static final String LOG_TAG = "ExternalProcessHanldle";

        private final IBinder mToken;
        private int mAcquisitionCount;

        public ExternalProcessHandle(IBinder token) {
            mToken = token;
            try {
                token.linkToDeath(this, 0);
            } catch (RemoteException re) {
                Slog.e(LOG_TAG, "Couldn't register for death for token: " + mToken, re);
            }
        }

        public void unlinkFromOwnDeathLocked() {
            mToken.unlinkToDeath(this, 0);
        }

        @Override
        public void binderDied() {
            synchronized (service) {
                if (hasExternalProcessHandles() &&
                        externalProcessTokenToHandle.get(mToken) != null) {
                    removeExternalProcessHandleInternalLocked(mToken);
                }                        
            }
        }
    }
}